#include<bits/stdc++.h>

using namespace std;

int main() {
    double a, b, c;
    double area;
    cin >> a >> b >> c;
    double s = (a + b + c) / 2;
    if (s > a && s > b && s > c) {
        area = sqrt(s * (s - a) * (s - b) * (s - c));
        printf("%.2f", area);
    } else {
        cout << "No Solution" << endl;
    }

    return 0;
}
